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Cosmos/source2/Compiler/Cosmos.Compiler.DebugStub/DebugStub.cs
kudzu_cp 812603b385
2011-07-18 01:09:56 +00:00

999 lines
35 KiB
C#
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Cosmos.Compiler.Assembler;
using Cosmos.Compiler.Assembler.X86;
using Cosmos.Compiler.Debug;
using Cosmos.Compiler.XSharp;
namespace Cosmos.Compiler.DebugStub {
public class DebugStub : CodeGroup {
protected const uint VidBase = 0xB8000;
static public int mComNo = 0;
static protected UInt16[] mComPortAddresses = { 0x3F8, 0x2F8, 0x3E8, 0x2E8 };
static public UInt16 mComAddr;
static public UInt16 mComStatusAddr;
// Caller's EBP
static public DataMember32 CallerEBP;
// Caller's EIP
static public DataMember32 CallerEIP;
// Caller's ESP
static public DataMember32 CallerESP;
static public class Tracing {
public const byte Off = 0;
public const byte On = 1;
}
// Current status of OS Debug Stub
static public class Status {
public const byte Run = 0;
public const byte Break = 1;
}
static public class StepTrigger {
public const byte None = 0;
public const byte Into = 1;
public const byte Over = 2;
public const byte Out = 3;
}
public DebugStub(int aComNo) {
mComNo = aComNo;
mComAddr = mComPortAddresses[mComNo - 1];
mComStatusAddr = (UInt16)(mComAddr + 5);
// Old method, need to convert to fields
mAsm.DataMembers.AddRange(new DataMember[]{
// Tracing: 0=Off, 1=On
new DataMember("DebugTraceMode", 0),
// enum Status
new DataMember("DebugStatus", 0),
// Nesting control for non steppable routines
new DataMember("DebugSuspendLevel", 0),
// Nesting control for non steppable routines
new DataMember("DebugResumeLevel", 0),
// Ptr to the push all data. It points to the "bottom" after a PushAll op.
// Walk up to find the 8 x 32 bit registers.
new DataMember("DebugPushAllPtr", 0),
new DataMember("InterruptsEnabledFlag", 0),
// If set non 0, on next trace a break will occur
new DataMember("DebugBreakOnNextTrace", (uint)StepTrigger.None),
// For step out and over this is used to determine where the initial request was made
// EBP is logged when the trace is started and can be used to determine
// what level we are "at" relative to the original step start location.
new DataMember("DebugBreakEBP", 0),
// Command ID of last command received
new DataMember("DebugStub_CommandID", 0),
// Breakpoint addresses
new DataMember("DebugBPs", new int[256]),
//TODO: Move to DebugStub (new)
new DataMember("DebugWaitMsg", "Waiting for debugger connection...")
});
}
public abstract class Inlines : CodeBlock {
// INLINE
// Modifies: Stack, EDI, AL
// TODO: Modify X# to allow inlining better by using dynamic labels otherwise
// repeated use of an inline will fail with conflicting labels.
// TODO: Allow methods to emit a start label and return automatically
// and mark inlines so this does not happen.
protected void ReadComPortX32toStack(int xCount) {
for (int i = 1; i <= xCount; i++) {
// Make room on the stack for the address
Push(0);
// ReadByteFromComPort writes to EDI, then increments
EDI = ESP;
// Read address to stack via EDI
ReadBytesFromComPort(4);
}
}
protected void ReadBytesFromComPort(int xCount) {
for (int i = 1; i <= xCount; i++) {
Call<ReadByteFromComPort>();
}
}
protected void WriteBytesToComPort(int xCount) {
for (int i = 1; i <= xCount; i++) {
Call<WriteByteToComPort>();
}
}
}
public class BreakOnAddress : Inlines {
// Sets a breakpoint
// Serial Params:
// 1: x32 - EIP to break on, or 0 to disable breakpoint.
[XSharp(PreserveStack = true)]
public override void Assemble() {
// BP Address
ReadComPortX32toStack(1);
ECX.Pop();
// BP ID Number
// BP ID Number is sent after BP Address, becuase
// reading BP address uses AL (EAX).
EAX = 0;
Call<ReadALFromComPort>();
// Calculate location in table
// Mov [EBX + EAX * 4], ECX would be better, but our asm doesn't handle this yet
EBX = AddressOf("DebugBPs");
EAX = EAX << 2;
EBX.Add(EAX);
Memory[EBX] = ECX;
}
}
public class SendMethodContext : Inlines {
// sends a stack value
// Serial Params:
// 1: x32 - offset relative to EBP
// 2: x32 - size of data to send
[XSharp(PreserveStack = true)]
public override void Assemble() {
AL = (int)DsMsgType.MethodContext;
Call<WriteALToComPort>();
// offset relative to ebp
// size of data to send
ReadComPortX32toStack(2);
ECX.Pop();
EAX.Pop();
// now ECX contains size of data (count)
// EAX contains relative to EBP
ESI = Memory[CallerEBP];
ESI.Add(EAX);
Label = ".SendByte";
ECX.Compare(0);
JumpIf(Flags.Equal, ".AfterSendByte");
Call<WriteByteToComPort>();
ECX--;
Jump(".SendByte");
Label = ".AfterSendByte";
}
}
public class SendMemory : Inlines {
// sends a stack value
// Serial Params:
// 1: x32 - offset relative to EBP
// 2: x32 - size of data to send
[XSharp(PreserveStack = true)]
public override void Assemble() {
ReadComPortX32toStack(1);
//EAX.Pop();
//ESI = EBP;
//ESI.Add(EAX);
//ESI.Push();
// todo: adjust ESI to the actual offset
Label = "DebugStub_SendMemory_1";
AL = (int)DsMsgType.MemoryData;
Call<WriteALToComPort>();
//EAX.Pop();
//EAX.Push();
ReadComPortX32toStack(1);
Label = "DebugStub_SendMemory_2";
ECX.Pop();
ESI.Pop();
// now ECX contains size of data (count)
// ESI contains address
Label = "DebugStub_SendMemory_3";
Label = "DebugStub_SendMemory_SendByte";
new Compare { DestinationReg = Registers.ECX, SourceValue = 0 };
JumpIf(Flags.Equal, "DebugStub_SendMemory_After_SendByte");
Call<WriteByteToComPort>();
new Dec { DestinationReg = Registers.ECX };
Jump("DebugStub_SendMemory_SendByte");
Label = "DebugStub_SendMemory_After_SendByte";
}
}
public class SendTrace : Inlines {
// Modifies: EAX, ESI
public override void Assemble() {
Memory["DebugStatus", 32].Compare(Status.Run);
JumpIf(Flags.Equal, ".Normal");
AL = (int)DsMsgType.BreakPoint;
Jump(".Type");
Label = ".Normal";
AL = (int)DsMsgType.TracePoint;
Label = ".Type";
Call<WriteALToComPort>();
// Send Calling EIP.
ESI = AddressOf(CallerEIP);
WriteBytesToComPort(4);
}
}
public class SendText : Inlines {
// Input: Stack
// Output: None
// Modifies: EAX, ECX, EDX, ESI
public override void Assemble() {
// Write the type
AL = (int)DsMsgType.Message;
Call<WriteALToComPort>();
// Write Length
ESI = EBP;
ESI = ESI + 12;
ECX = Memory[ESI];
WriteBytesToComPort(2);
// Address of string
ESI = Memory[EBP + 8];
Label = ".WriteChar";
ECX.Compare(0);
JumpIf(Flags.Equal, ".Exit");
Call<WriteByteToComPort>();
ECX--;
// We are storing as 16 bits, but for now I will transmit 8 bits
// So we inc again to skip the 0
ESI++;
Jump(".WriteChar");
}
}
public class SendPtr : Inlines {
// Input: Stack
// Output: None
// Modifies: EAX, ECX, EDX, ESI
public override void Assemble() {
// Write the type
AL = (int)DsMsgType.Pointer;
Call<WriteALToComPort>();
// pointer value
ESI = Memory[EBP + 8];
WriteBytesToComPort(4);
}
}
public class WriteByteToComPort : Inlines {
// Input: ESI
// Output: None
// Modifies: EAX, EDX
//
// Sends byte at [ESI] to com port and does esi + 1
//
// This sucks to use the stack, but x86 can only read and write ports from AL and
// we need to read a port before we can write out the value to another port.
// The overhead is a lot, but compared to the speed of the serial and the fact
// that we wait on the serial port anyways, its a wash.
//
// This could be changed to use interrupts, but that then complicates
// the code and causes interaction with other code. DebugStub should be
// as isolated as possible from any other code.
public override void Assemble() {
// Sucks again to use DX just for this, but x86 only supports
// 8 bit address for literals on ports
DX = mComStatusAddr;
// Wait for serial port to be ready
// Bit 5 (0x20) test for Transmit Holding Register to be empty.
Label = ".Wait";
AL = Port[DX];
AL.Test(0x20);
JumpIf(Flags.Zero, ".Wait");
// Set address of port
DX = mComAddr;
// Get byte to send
AL = Memory[ESI];
// Send the byte
Port[DX] = AL;
ESI++;
}
}
public class ReadALFromComPort : Inlines {
// Modifies: AL, DX
public override void Assemble() {
DX = mComStatusAddr;
// Wait for port to be ready
Label = ".Wait";
AL = Port[DX];
AL.Test(0x01);
JumpIf(Flags.Zero, ".Wait");
// Set address of port
DX = mComAddr;
// Read byte
AL = Port[DX];
}
}
// Called before Kernel runs. Inits debug stub, etc
public class Init : CodeBlock {
public override void Assemble() {
Call<Cls>();
Call<DisplayWaitMsg>();
Call<InitSerial>();
Call<WaitForDbgHandshake>();
Call<Cls>();
}
}
public class WaitForDbgHandshake : Inlines {
public override void Assemble() {
// "Clear" the UART out
AL = 0;
Call<WriteALToComPort>();
// QEMU (and possibly others) send some garbage across the serial line first.
// Actually they send the garbage inbound, but garbage could be inbound as well so we
// keep this.
// To work around this we send a signature. DC then discards everything before the signature.
// QEMU has other serial issues too, and we dont support it anymore, but this signature is a good
// feature so we kept it.
Push(Consts.SerialSignature);
ESI = ESP;
WriteBytesToComPort(4);
// Restore ESP, we actually dont care about EAX or the value on the stack anymore.
EAX.Pop();
// We could use the signature as the start signal, but I prefer
// to keep the logic separate, especially in DC.
AL = (int)DsMsgType.Started; // Send the actual started signal
Call<WriteALToComPort>();
Call<WaitForSignature>();
Call<ProcessCommandBatch>();
}
}
public class InitSerial : CodeBlock {
// SERIAL DOCS
//
// All information relating to our serial usage should be documented in
// this comment.
//
// We do not use IRQs for debugstub serial. This is becuase DebugStub (DS)
// MUST be:
// - As simple as possible
// - Interact as minimal as possible wtih normal Cosmos code because
// the debugstub must *always* work even if the normal code is fubarred
//
// The serial port that is used for DS should be "hidden" from Cosmos main
// so that Cosmos main pretends it does not exist.
//
// IRQs would create a clash/mix of code.
// This does make the serial code in DebugStub inefficient, but its well worth
// the benefits received by following these rules.
//
// Baud rate is set to 115200. Likely our code could not exceed this rate
// anyways the way it is written and there are compatibility issues on some
// hardware above this rate.
//
// We assume a minimum level of a 16550A, which should be no problem on any
// common hardware today. VMWare emulates the 16550A
//
// We do not handle flow control for outbound data (DS --> DC).
// The DebugConnector (DC, the code in the Visual Studio side) however is threaded
// and easily should be able to receive data faster than we can send it.
// Most things are transactional with data being sent only when asked for, but
// with tracing we do send a data directly.
//
// Currently there is no inbound flow control either (DC --> DS)
// For now we assume all commands in bound are 16 bytes or less to ensure
// that they fit in the FIFO. Commands in DS must wait for a command ID ACK
// before sending another command.
// See notes in ProcessCommand.
public override void Assemble() {
// http://www.nondot.org/sabre/os/files/Communication/ser_port.txt
// Disable interrupts
DX = (UInt16)(mComAddr + 1);
AL = 0;
Port[DX] = AL;
// Enable DLAB (set baud rate divisor)
DX = (UInt16)(mComAddr + 3);
AL = 0x80;
Port[DX] = AL;
// 0x01 - 0x00 - 115200
// 0x02 - 0x00 - 57600
// 0x03 - 0x00 - 38400
//
// Set divisor (lo byte)
DX = mComAddr;
AL = 0x01;
Port[DX] = AL;
// hi byte
DX = (UInt16)(mComAddr + 1);
AL = 0x00;
Port[DX] = AL;
// 8N1
DX = (UInt16)(mComAddr + 3);
AL = 0x03;
Port[DX] = AL;
// Enable FIFO, clear them
// Set 14-byte threshold for IRQ.
// We dont use IRQ, but you cant set it to 0
// either. IRQ is enabled/diabled separately
DX = (UInt16)(mComAddr + 2);
AL = 0xC7;
Port[DX] = AL;
// 0x20 AFE Automatic Flow control Enable - 16550 (VMWare uses 16550A) is most common and does not support it
// 0x02 RTS
// 0x01 DTR
// Send 0x03 if no AFE
DX = (UInt16)(mComAddr + 4);
AL = 0x03;
Port[DX] = AL;
}
}
public class DisplayWaitMsg : CodeBlock {
// http://wiki.osdev.org/Text_UI
// Later can cycle for x changes of second register:
// http://wiki.osdev.org/Time_And_Date
public override void Assemble() {
ESI = AddressOf("DebugWaitMsg");
// 10 lines down, 20 cols in
EDI = VidBase + (10 * 80 + 20) * 2;
// Read and copy string till 0 terminator
Label = ".ReadChar";
AL = Memory[ESI, 8];
AL.Compare(0);
JumpIf(Flags.Equal, ".AfterMsg");
ESI++;
Memory[EDI, 8] = AL;
EDI++;
EDI++;
Jump(".ReadChar");
//TODO: Local labels in X#
Label = ".AfterMsg";
}
}
public class WriteALToComPort : CodeBlock {
// Input: AL
// Output: None
// Modifies: EDX, ESI
public override void Assemble() {
EAX.Push();
ESI = ESP;
Call<WriteByteToComPort>();
// Is a local var, cant use Return(4). X# issues the return.
// This also allow the function to preserve EAX.
EAX.Pop();
}
}
public class WriteAXToComPort : Inlines {
// Input: AX
// Output: None
// Modifies: EDX, ESI
public override void Assemble() {
EAX.Push();
ESI = ESP;
WriteBytesToComPort(2);
// Is a local var, cant use Return(4). X# issues the return.
// This also allow the function to preserve EAX.
EAX.Pop();
}
}
public class WriteEAXToComPort : Inlines {
// Input: EAX
// Output: None
// Modifies: EDX, ESI
public override void Assemble() {
EAX.Push();
ESI = ESP;
WriteBytesToComPort(4);
// Is a local var, cant use Return(4). X# issues the return.
// This also allow the function to preserve EAX.
EAX.Pop();
}
}
public class ProcessCommandBatch : CodeBlock {
public override void Assemble() {
Call<ProcessCommand>();
// See if batch is complete
AL.Compare(DsCommand.BatchEnd);
JumpIf(Flags.Equal, "DebugStub_ProcessCommandBatch_Exit");
// Loop and wait
Jump("DebugStub_ProcessCommandBatch");
Label = "DebugStub_ProcessCommandBatch_Exit";
}
}
public class WaitForSignature : CodeBlock {
public override void Assemble() {
EBX = 0;
Label = "DebugStub_WaitForSignature_Read";
Call<ReadALFromComPort>();
BL = AL;
EBX.RotateRight(8);
EBX.Compare(Consts.SerialSignature);
JumpIf(Flags.NotEqual, "DebugStub_WaitForSignature_Read");
//TODO: Always emit and exit label and then make a Exit method which can
// automatically use it. I think a label might already exist.
Label = "DebugStub_WaitForSignature_Exit";
}
}
public class Cls : CodeBlock {
public override void Assemble() {
ESI = VidBase;
// TODO: X# upgrade this
Label = "DebugStub_Cls_More";
//TODO: Fix to direct memory write after we fix the X# bug with Memory[ESI, 8] = 0x0A;
AL = 0x00;
Memory[ESI, 8] = AL; // Text
ESI++;
AL = 0x0A;
Memory[ESI, 8] = AL; // Colour
ESI++;
ESI.Compare(VidBase + 25 * 80 * 2);
JumpIf(Flags.LessThan, "DebugStub_Cls_More");
}
}
public class SendRegisters : Inlines {
public override void Assemble() {
AL = (int)DsMsgType.Registers; // Send the actual started signal
Call<WriteALToComPort>();
ESI = Memory["DebugPushAllPtr"];
WriteBytesToComPort(32);
ESI = AddressOf(CallerESP);
WriteBytesToComPort(4);
ESI = AddressOf(CallerEIP);
WriteBytesToComPort(4);
}
}
public class SendFrame : Inlines {
public override void Assemble() {
AL = (int)DsMsgType.Frame;
Call<WriteALToComPort>();
int xCount = 8 * 4;
EAX = (uint)xCount;
Call<WriteAXToComPort>();
ESI = Memory[CallerEBP];
ESI.Add(8); // Dont transmit EIP or old EBP
WriteBytesToComPort(xCount);
}
}
public class SendStack : CodeBlock {
public override void Assemble() {
AL = (int)DsMsgType.Stack;
Call<WriteALToComPort>();
// Send size of bytes
ESI = Memory[CallerESP];
EAX = Memory[CallerEBP];
EAX.Sub(ESI);
Call<WriteAXToComPort>();
// Send actual bytes
//
// Need to reload ESI, WriteAXToCompPort modifies it
ESI = Memory[CallerESP];
Label = ".SendByte";
ESI.Compare(Memory[CallerEBP, 32]);
JumpIf(Flags.Equal, ".Exit");
Call<WriteByteToComPort>();
Jump(".SendByte");
}
}
public class ProcessCommand : CodeBlock {
// Modifies: AL, DX (ReadALFromComPort)
// Returns: AL
public override void Assemble() {
Call<ReadALFromComPort>();
// Some callers expect AL to be returned, so we preserve it
// in case any commands modify AL.
//TODO: But in ASM wont let us push AL, so we push EAX for now
EAX.Push();
// Noop has no data at all (see notes in client DebugConnector), so skip Command ID
AL.Compare(DsCommand.Noop);
JumpIf(Flags.Equal, "DebugStub_ProcessCmd_Exit");
// Read Command ID
Call<ReadALFromComPort>();
Memory["DebugStub_CommandID"] = EAX;
// Get AL back so we can compare it, but also put it back for later
EAX.Pop();
EAX.Push();
#region handle commands
AL.Compare(DsCommand.TraceOff);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_TraceOff_After");
Memory["DebugTraceMode", 32] = Tracing.Off;
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_TraceOff_After";
AL.Compare(DsCommand.TraceOn);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_TraceOn_After");
Memory["DebugTraceMode", 32] = Tracing.On;
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_TraceOn_After";
AL.Compare(DsCommand.Break);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_Break_After");
Call<Break>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_Break_After";
AL.Compare(DsCommand.BreakOnAddress);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_BreakOnAddress_After");
Call<BreakOnAddress>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_BreakOnAddress_After";
AL.Compare(DsCommand.SendMethodContext);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_SendMethodContext_After");
Call<SendMethodContext>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_SendMethodContext_After";
AL.Compare(DsCommand.SendMemory);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_SendMemory_After");
Call<SendMemory>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_SendMemory_After";
AL.Compare(DsCommand.SendRegisters);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_SendRegisters_After");
Call<SendRegisters>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_SendRegisters_After";
AL.Compare(DsCommand.SendFrame);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_SendFrame_After");
Call<SendFrame>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_SendFrame_After";
AL.Compare(DsCommand.SendStack);
JumpIf(Flags.NotEqual, "DebugStub_ProcessCmd_SendStack_After");
Call<SendStack>();
Jump("DebugStub_ProcessCmd_ACK");
Label = "DebugStub_ProcessCmd_SendStack_After";
Label = "DebugStub_ProcessCmd_ACK";
// We acknowledge receipt of the command, not processing of it.
// We have to do this because sometimes callers do more processing
// We ACK even ones we dont process here, but do not ACK Noop.
// The buffers should be ok becuase more wont be sent till after our NACK
// is received.
// Right now our max cmd size is 2 (Cmd + Cmd ID) + 5 (Data) = 7.
// UART buffer is 16.
// We may need to revisit this in the future to ack not commands, but data chunks
// and move them to a buffer.
// The buffer problem exists only to inbound data, not outbound data (relative to DebugStub)
AL = DsMsgType.CmdCompleted;
Call<WriteALToComPort>();
EAX = Memory["DebugStub_CommandID", 32];
#endregion
Call<WriteALToComPort>();
Label = "DebugStub_ProcessCmd_After";
Label = "DebugStub_ProcessCmd_Exit";
// Restore AL for callers who check the command and do
// further processing, or for commands not handled by this routine.
EAX.Pop();
}
}
public class Executing : CodeBlock {
// This is the secondary stub routine. After the primary (main) has decided we should do some debug
// activities, this one is called.
//
// Modifies: EAX, EDI, ECX
public override void Assemble() {
// Look for a possible matching BP
EAX = Memory[CallerEIP];
EDI = AddressOf("DebugBPs");
ECX = 256;
new Scas { Prefixes = InstructionPrefixes.RepeatTillEqual, Size = 32 };
JumpIf(Flags.NotEqual, "DebugStub_Executing_AfterBreakOnAddress");
Call<Break>();
Jump("DebugStub_Executing_Normal");
Label = "DebugStub_Executing_AfterBreakOnAddress";
// See if we are stepping
//
// F11
Memory["DebugBreakOnNextTrace", 32].Compare(StepTrigger.Into);
//Old, can delete this line: CallIf(Flags.Equal, "DebugStub_Break");
//TODO: I think we can use a using statement to create this type of block
// and emit asm
// using (var xBlock = new AsmBlock()) {
// JumpIf(something, xBlock.End/Begin);
// also can do xBlock.Break();
// }
//TODO: If statements can probably be done with anonymous delegates...
JumpIf(Flags.NotEqual, "DebugStub_ExecutingStepIntoAfter");
Call<Break>();
//TODO: Allow creating labels but issuing them later, then we can
// call them with early binding
//TODO: End - can be exit label for each method, allowing Jump(Begin/End) etc... Also make a label type and allwo Jump overload to the label itself. Or better yet, End.Jump()
Jump("DebugStub_Executing_Normal");
Label = "DebugStub_ExecutingStepIntoAfter";
//
// F10
Memory["DebugBreakOnNextTrace", 32].Compare(StepTrigger.Over);
JumpIf(Flags.NotEqual, "DebugStub_ExecutingStepOverAfter");
Label = "Debug__StepOver__";
EAX = Memory[CallerEBP];
EAX.Compare(Memory["DebugBreakEBP", 32]);
// If EBP and start EBP arent equal, dont break
// Dont use Equal because we aslo need to stop above if the user starts
// the step at the end of a method and next item is after a return
CallIf(Flags.LessThanOrEqualTo, "DebugStub_Break");
Jump("DebugStub_Executing_Normal");
Label = "DebugStub_ExecutingStepOverAfter";
//
// Shift-F11
Memory["DebugBreakOnNextTrace", 32].Compare(StepTrigger.Out);
JumpIf(Flags.NotEqual, "DebugStub_ExecutingStepOutAfter");
EAX = Memory[CallerEBP];
EAX.Compare(Memory["DebugBreakEBP", 32]); // TODO: X# JumpIf(EAX == Memory[...... or better yet if(EAX==Memory..., new Delegate { Jump.... Jump should be handled specially so we dont jump around jumps... TODO: Also allow Compare(EAX, 0), in fact force this new syntax
JumpIf(Flags.Equal, "DebugStub_Executing_Normal");
CallIf(Flags.LessThanOrEqualTo, "DebugStub_Break");
Jump("DebugStub_Executing_Normal");
Label = "DebugStub_ExecutingStepOutAfter";
Label = "DebugStub_Executing_Normal";
// If tracing is on, send a trace message
// Tracing isnt really used any more, was used
// by the old stand alone debugger. Might be upgraded
// and resused in the future.
Memory["DebugTraceMode", 32].Compare(Tracing.On);
CallIf(Flags.Equal, "DebugStub_SendTrace");
// Is there a new incoming command? We dont want to wait for one
// if there isn't one already here. This is a passing check.
Label = "DebugStub_CheckForCmd"; //TODO: ".CheckForCmd" and make it local to our class
DX = (ushort)(mComAddr + 5u);
AL = Port[DX];
AL.Test(0x01);
// If no command waiting, break from loop
JumpIf(Flags.Zero, "DebugStub_CheckForCmd_Break");
Call<ProcessCommand>();
// See if there are more commands waiting
Jump("DebugStub_CheckForCmd");
Label = "DebugStub_CheckForCmd_Break";
}
}
public class ReadByteFromComPort : CodeBlock {
// Input: EDI
// Output: [EDI]
// Modified: AL, DX, EDI (+1)
//
// Reads a byte into [EDI] and does EDI + 1
// http://wiki.osdev.org/Serial_ports
public override void Assemble() {
Call<ReadALFromComPort>();
Memory[EDI, 8] = AL;
EDI++;
}
}
public class Break : CodeBlock {
// Should only be called internally by DebugStub. Has a lot of preconditions
// Externals should use BreakOnNextTrace instead
public override void Assemble() {
// Reset request in case we are currently responding to one or we hit a fixed breakpoint
// before our request could be serviced (if one existed)
Memory["DebugBreakOnNextTrace", 32] = StepTrigger.None;
Memory["DebugBreakEBP", 32] = 0;
// Set break status
Memory["DebugStatus", 32] = Status.Break;
Call<SendTrace>();
// Wait for a command
Label = "DebugStub_WaitCmd";
// Check for common commands
Call<ProcessCommand>();
// Now check for commands that are only valid in break state
// or commands that require additional handling while in break
// state.
AL.Compare(DsCommand.Continue);
JumpIf(Flags.Equal, "DebugStub_Break_Exit");
AL.Compare(DsCommand.StepInto);
JumpIf(Flags.NotEqual, "DebugStub_Break_StepInto_After");
Memory["DebugBreakOnNextTrace", 32] = StepTrigger.Into;
Jump("DebugStub_Break_Exit");
Label = "DebugStub_Break_StepInto_After";
AL.Compare(DsCommand.StepOver);
JumpIf(Flags.NotEqual, "DebugStub_Break_StepOver_After");
Memory["DebugBreakOnNextTrace", 32] = StepTrigger.Over;
EAX = Memory[CallerEBP];
Memory["DebugBreakEBP", 32] = EAX;
Jump("DebugStub_Break_Exit");
Label = "DebugStub_Break_StepOver_After";
AL.Compare(DsCommand.StepOut);
JumpIf(Flags.NotEqual, "DebugStub_Break_StepOut_After");
Memory["DebugBreakOnNextTrace", 32] = StepTrigger.Out;
EAX = Memory[CallerEBP];
Memory["DebugBreakEBP", 32] = EAX;
Jump("DebugStub_Break_Exit");
Label = "DebugStub_Break_StepOut_After";
// Loop around and wait for another command
Jump("DebugStub_WaitCmd");
Label = "DebugStub_Break_Exit";
Memory["DebugStatus", 32] = Status.Run;
}
}
public class TracerEntry : CodeBlock {
// 0 = Not in, 1 = already running
public DataMember32 IsRunning;
[XSharp(IsInteruptHandler = true)]
public override void Assemble() {
// Main entry point for the DebugStub which is executed at the
// beginning of all IL ops.
// EBP is restored by PopAll, but SendFrame uses it. Could
// get it from the PushAll data, but this is easier.
Memory[CallerEBP] = EBP;
// Could also get ESP from PushAll but this is easier
// Another reason to do it here is that soem day we may need to use
// the stack before PushAll.
//
// We cant modify any registers since we havent done PushAll yet
// Maybe we could do a sub(4) on memory direct..
// But for now we remove from ESP which the call to us produces,
// store ESP, then restore ESP so we don't cause stack corruption.
ESP = ESP + 12; // 12 bytes for EFLAGS, CS, EIP
Memory[CallerESP] = ESP;
ESP = ESP - 12;
// If debug stub is in break, and then an IRQ happens, the IRQ
// can call DebugStub again. This causes two DebugStubs to
// run which causes havoc. So we only allow one to run.
// We arent multi threaded yet, so this works fine.
// IRQ's are disabled between Compare and JumpIf so an IRQ cant
// happen in between them which could also cause double entry.
DisableInterrupts();
Memory["DebugSuspendLevel", 32].Compare(0);
JumpIf(Flags.Equal, "DebugStub_Running");
// DebugStub is already running, so exit.
// But we need to see if IRQs are disabled.
// If IRQ disabled, we dont reenable them after our disable
// in this routine.
Memory["InterruptsEnabledFlag", 32].Compare(0);
JumpIf(Flags.Equal, "DebugStub_Return");
EnableInterrupts();
Jump("DebugStub_Return");
Label = "DebugStub_Running";
Memory[IsRunning, 32].Compare(0);
JumpIf(Flags.Equal, "DebugStub_Start");
// If we made it this far we exit because DebugStub is already running.
// We need to see if IRQs were originally enabled or disabled and
// re-enable them if they were enabled on entry.
Jump("DebugStub_CheckIntAndReturn");
// All clear, mark that we are entering the debug stub
Label = "DebugStub_Start";
Memory[IsRunning] = 1;
// DS is now marked not to re-enter, so re-enable interrupts if
// they were enabled on entry
Memory["InterruptsEnabledFlag", 32].Compare(0);
JumpIf(Flags.Equal, "DebugStub_NoSTI");
EnableInterrupts();
// Call secondary debug stub
Label = "DebugStub_NoSTI";
PushAll();
Memory["DebugPushAllPtr", 32] = ESP;
// We just pushed all registers to the stack so we can use them
// So we get the stack pointer and add 32. This skips over the
// registers we just pushed.
EBP = ESP;
EBP = EBP + 32; // We dont need to restore this becuase it was pushed as part of PushAll32
// Get actual EIP of caller.
EAX = Memory[EBP];
// EIP is pointer to op after our call. We subtract 1 for the opcode size of Int3
// Note - when we used call it was 5 (the size of our call + address)
// so we get the EIP as IL2CPU records it. Its also useful for when we will
// be changing ops that call this stub.
EAX--;
// Store it for later use.
Memory[CallerEIP] = EAX;
// Call secondary stub
Call<Executing>();
// Restore registers
PopAll();
// Setting the DebugRuning flag is atomic, but in the future
// we might have other code as we do in the entry to check.
// So just to be safe, we disable interrupts while we do this.
DisableInterrupts();
// Complete, mark that DebugStub is complete
Memory[IsRunning] = 0;
Label = "DebugStub_CheckIntAndReturn";
// Re-enable interrupts if needed. This happens on normal exit, or call from above
// when there would have been a re-entry to DS.
Memory["InterruptsEnabledFlag", 32].Compare(0);
JumpIf(Flags.Equal, "DebugStub_Return");
EnableInterrupts();
Label = "DebugStub_Return";
}
}
}
public class DebugPoint : CodeGroup {
public class DebugSuspend : CodeBlock {
public override void Assemble() {
Memory["DebugSuspendLevel", 32]++;
}
}
public class DebugResume : CodeBlock {
public override void Assemble() {
Memory["DebugSuspendLevel", 32]--;
}
}
}
}
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